Allows programmatic registration of subflows needed by a flow execution being
tested, see registerSubflow(Flow) . Subflows registered are
typically stubs that verify parent flow input and output scenarios.
Also supports programmatic registration of additional custom services needed
by a flow (such as Actions) managed in a backing Spring
ConfigurableBeanFactory . See the
registerBean(String, Object) method. Beans registered are typically
mocks or stubs of business services invoked by the flow.